This invention relates to a method and apparatus for threading the end of a web from a jumbo roll or equivalent through a winder along a path determined by members guiding the web.
At present, the threading of the end of a web through a winder is carried out by tearing the end of the web to a wedge-shaped form and leading the end of the web through the winder, e.g. a carrier-drum slitter-winder, onto the carrier drums by means of a threading device. Thereupon the wedge-shaped end of the web is removed, and the slit component webs are wound around paper cores in known manner before the winding is started. It is a drawback of this method that the threading of the web is very slow and, as a rule, requires two or three workers, because the end of the web must first be torn to a wedge-shaped form, the creeping of the winder is slow, and the removal of the wedge-shaped end takes time. Moreover, the prior art method requires air blowers, belts, etc. as auxiliary equipment for the threading of the web.
In Finnish Patent No. 69,439, a method and device are described for threading the end of a web from a jumbo roll or equivalent through a winder along a path determined by the members guiding the web. In this prior art solution, the end of the web is passed from the jumbo roll through the winder at full width by grasping the end of the web placed on the jumbo roll and winding the web around a fetching and grasping device for a desired number of revolutions, whereupon the web is passed through the winder in doubled-over fashion so that the web is unwound at the same time both from the jumbo roll and from the fetching and grasping device.
A drawback of the method and device in accordance with Finnish Patent No. 69,439 is that the innermost layers formed on the paper core are unsuitable for printing, for which reason the roll cannot be unwound completely to the end. This causes a loss of material. Moreover, this prior art method and device require relatively complicated equipment, because the web is passed through the winder in doubled over fashion.